It is the aim of the Laboratory to concentrate on theoretical, empirical, and methodological issues in the substantive area of cognitive psychology. Special emphasis is to be placed on the tailoring of mathematical models and statistical techniques to specific research problems. To this end, six sets of research questions are outlined, each of which is directed toward the single broad problem of understanding cognitive abilities. These questions involve (1) some parameters of individual differences in the development of linguistic abilities; (2) learning rates and aptitude-treatment interactions; (3) problem solving; (4) spatial visualization and imagery; (5) the organization of memory; and (6) techniques for obtaining individual parameters within certain models. The long range goals and significance of the proposed research lie in the development of methodology and theory for understanding human abilities and individual differences within the context of modern cognitive psychology. BIBLIOGRAPHIC REFERENCES: de Leeuw, J., Young, F.W., and Takane, Y. Additive structure in qualitative data: An alternating least squares method with optimal scaling features. (Psychometric Lab. Report 140). Chapel Hill, N.C.: Psychometric Laboratory, Univ. of North Carolina, 1975. (In press, Psychometrika.)